Word offers a handy tool in its Compare and Merge Documents feature. This tool allows you to compare two documents to illustrate the differences between the two as track changes and/or merge two documents together (also using track changes).
To access the Compare and Merge feature, with your original document open, click Tools > Compare and Merge Documents.
A Windows dialog box will appear. From this box, navigate to your second, modified document and select it to open.
Notice in this dialog box that you have several options for how you want to proceed. There are two checkboxes, one for Legal blackline and one for Find formatting. If you want to MERGE your documents, you should not select the Legal blackline checkbox. Checking off the Find formatting checkbox will show all differences in formatting, not just differences in the text contained in the document.
For this example, let's not choose Legal blackline. You'll notice that if you have a document selected in the dialog box above, the button which typically says Open now says Merge. Click the dropdown arrow next to the Merge label to view an additional list of options, as shown below.
You can opt to Merge your selected document into the current document, which places all changes from the modified document into the original document, or you can merge into a new document, which leaves both your original and modified documents untouched and creates a third, separate document to display the results of your merge.
In this example, I'm simply choosing Merge, which places the changes in the current (original) document. When I click Merge, I receive the following message from Word that explains that the documents being merged have one or more conflicing formatting changes. It further explains that Word can only store one set of changes in the final document. Therefore, you need to choose which document has the formatting you want to keep.
Word offers to keep the current (original) document formatting versus the target (modified) document's formatting. Since I know I've made formatting changes in the modified document that I want to show in the merge, I switch and choose the Target document, then I click Continue with Merge.
The results of the merge are depicted below.
But wait, you say…those look like tracked changes! Exactly right. The folks at Microsoft must have realized you might not want to keep all of the new changes in the modified document when you merge changes. Therefore, each of the differences is shown as a Tracked Change and can be accepted or rejected individually, using the Track Changes toolbar.
Let's back up a few steps and see what happens when we choose Legal Blackline in that Compare and Merge Documents dialog box.
Notice that when the legal blackline checkbox is selected, the label on the button to the right changes from Merge to Compare. We are not merging any changes in a legal blackline; we're simply illustrating the differences between two documents. These differences and the resulting comparison document will also display and function as tracked changes, as you can see below.
While the two are closely related, Merging and Comparing documents are two different animals. One example of a great time to merge your documents? When you and several other coworkers have made changes to the same document, saved separately, that sort of collaboration can be a mess to keep track of. However, if you merge all of your changes into the same document...Presto! You now have everyone's ideas in the same workspace, where each can be accepted or rejected as needed.
Another item worth noting for legal professionals, is that some law firms find Word's legal blackline feature to be lacking, so they purchase separate software that performs the blacklining comparison feature for them. One such product is Workshare DeltaView. While Word does a satisfactory job in some instances, for some jobs, a third party application may be just the ticket.